The osteoporosis means a condition where decrease of the absolute amount of a bone is caused, but where no qualitative change of the bone is involved. A bone is constantly absorbed and formed, and if a difference between the absorption ratio and the formation ratio is made so that the bone formation becomes negative in balance, then osteoporosis occurs. The bone absorption is made by osteoclasts, and as differentiation and activation of the osteoclasts become greater, the bone absorption ratio becomes higher. On the other hand, the bone formation is made by osteoblasts, and as differentiation and activation of the osteoblasts become greater, the bone formation ratio becomes higher.
The osteoarthritis is a malady such that a chronic regressive change and a chronic proliferative change occur simultaneously to a joint to thus change the form of the joint. As a result, an articular cartilage is gradually abraded and lost, so that a bone becomes exposed. In the articular cartilage, there is not any vascular system, and particularly, articular sliding part cartilage cells and rib cartilage tissue are more difficult to repair or regenerate than bone tissue where there is a vascular system. Particularly, if the bone tissue which supports the articular cartilage becomes sparse (osteoporosis), then the function of the articular part is hindered, so that the osteoarthritis is caused.
The pressure ulcer means a condition where during long-term lying in bed, skin and soft part tissue in a place where a bone is projected undergo circulation disable due to long-term press between the bone and the bed to thus fall into necrosis.
As an effect of a peptide on the above symptoms, an effect on the osteoarthritis is reported. For example known are the following: a joint-strengthening drink comprising a collagen peptide and a glucosamine salt as effective components and having a pH of 2 to 5 (refer to patent document 1 below); an improving drug for rheumatoid arthritis or the osteoarthritis which agent is obtained by decomposing a collagen component or a gelatin component using a collagenase enzyme and comprises a tripeptide of Gly-X-Y in amino acid sequence as an effective component (refer to patent document 2 below); and an oral articular disable curing drug or functional food being characterized by comprising: at least one member selected from the group consisting of collagen and collagen peptides; an amino saccharide; and at least one member selected from the group consisting of mucopolysaccharides and uronic acid (refer to patent document 3 below).
[Patent document 1]    JP-A-2002-125638
[Patent document 2]    JP-A-2002-255847
[Patent document 3]    JP-A-2003-048850